A process for producing nitroguanidine derivatives having an insecticidal activity has been disclosed in Japanese Patent No. 2779403, Japanese Patent No. 2546003, Japanese Patent No. 2766848. However, for example, as described in Japanese Patent No. 2766848, the problem occurs in the production method that substitution reactions between isothiourea derivatives and amines are used thereby releasing mercaptans as by-products having a strong distasteful odor. As an alternative method, in Japanese Patent Laid-open No. 2000-103776, there has been disclosed a process for producing nitroisourea derivatives in which nitroisourea derivatives and amines or a salt thereof are reacted at the pH of 7.0 to 9.0. However, in a production method according to this method, the desired yield of the nitroisourea derivatives are not sufficiently high and thus the method is economically disadvantageous in some cases.
Patent Document 1: Japanese Patent No. 2779403
Patent Document 2: Japanese Patent No. 2546003
Patent Document 3: Japanese Patent No. 2766848
Patent Document 4: Japanese Patent Laid-open No. 2000-103776